ureter n : either of a pair of thick-walled tubes that carry urine from the kidney to the urinary bladder

English

Noun

ureter (plural: ureters)

1. either of the two long, narrow ducts that carry urine from the kidneys to the urinary bladder

Translations

ureter

• Czech: močovod
• Finnish: virtsanjohdin
• Polish: moczowód
• Russian: мочеточник (močetóčnik)

Derived terms

• ureteral
• ureteric

See also

• urethra

In human anatomy, the ureters are muscular ducts that propel urine from the kidneys to the urinary bladder. In the adult, the ureters are usually 25-30cm (10-12 inches)long.

In humans, the ureters arise from the renal pelvis on the medial aspect of each kidney before descending towards the bladder on the front of the psoas major muscle. The ureters cross the pelvic brim near the bifurcation of the iliac arteries (which they run over). This "pelviureteric junction" is a common site for the impaction of kidney stones (the other being the ureterovesical valve). The ureters run posteroinferiorly on the lateral walls of the pelvis. They then curve anteriormedially to enter the bladder through the back, at the vesicoureteric junction, running within the wall of the bladder for a few centimeters. The backflow of urine is prevented by valves known as ureterovesical valves, pressure from the filling of the bladder, and the tone of the muscle in the bladder wall.

In the female, the ureters pass through the mesometrium on the way to the urinary bladder.

Histology

The ureter has a diameter of about 3 millimeters, and the lumen is star-shaped. Like the bladder, it is lined with transitional epithelium, and contains layers of smooth muscle, thereby being under autonomic control.

The epithelial cells of the ureter are stratified (in many layers), are normally round in shape but become squamous (flat) when stretched. The lamina propria is thick and elastic (as it is important that it is impermeable).

There are two spiral layers of smooth muscle in the ureter wall, an inner loose spiral, and an outer tight spiral. The inner loose spiral is sometimes described as longitudinal, and the outer as circular, (this is the opposite to the situation in the gastrointestinal tract). The distal third of the ureter contains another layer of outer longitudinal muscle.

The adventitia of the ureter, like elsewhere is composed of fibrous connective tissue, that binds it to adjacent tissues.

Diseases and disorders

Medical problems that can affect the ureter include:

• cancer of the ureter
• passage of kidney stones - especially at the uteropelvic junctions, where they cross the iliac vessels and their entrance to the bladder.
• ureterocele
• megaureter
• vesico-ureteric reflux
• anatomical abnormalities, such as duplexing and ectopia.

External links

• - "Posterior Abdominal Wall: Internal Structure of a Kidney"
• - "Relationship of the ureter to the uterine artery."
• - "Mid-sagittal section of male pelvis."
• - "Mammal, ureter (LM, Medium)"
• - "Ureter"

Additional images

Image:Illu bladder.jpg|Bladder Image:Illu kidney2.jpg|Frontal section through the kidney Image:Illu ureters wall.jpg|Wall of the ureter.

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